As integrated circuits become smaller, leakage power is becoming an increasing ratio of the total power, and ways to lessen its impact are needed. For example, as devices are made smaller, the power supply voltage may be correspondingly reduced. However, this may not achieve an adequate reduction in leakage power dissipation. Instead, alternative techniques are employed to reduce leakage power. One of those techniques employed is to use power gating to isolate the power supply voltage in groups of circuits at controlled times. The power gated circuits are used to control power such that the entire integrated circuit is not turned on at one time, and rather the power can be channeled to a predetermined area of the integrated circuit. However, turning on the power gated circuits can result in a rush of current causing an IR drop issue, which is essentially a voltage drop on the global power supply due to a flow of current (I) through a length of metal exhibiting resistance (R).
One technique employed to overcome this issue in power gated circuits is to daisy chain the power gate cells with delayed enable signals or grouping power gate cells with staged enable signals. An issue with these configurations is that the first cells in the chain or the first group of cells to be enabled are subjected to more sustained current rush and after many power gating cycles these cells become predisposed to electromigration failure.
Accordingly, there exists a need in the art to overcome the deficiencies and limitations described hereinabove.